Pneumatic cartridge valves are utilized in a great number of pneumatically operated mechanisms, for example in glass machines, particularly the well-known I.S. machine.
To operate such mechanisms firstly, at an appropriate time, a supply of compressed air at a controlled pressure must be provided and secondly, again at an appropriate time, air must be exhausted from the mechanism under controlled conditions.
The control of such supply and exhaust to the various mechanisms is often provided by use of a valve block which comprises a number of valves, conventionally an on/off valve for controlling the supply of operating air to the mechanism and for connecting such air to exhaust, and separate restrictor valves to control the rate of supply of operating air to the mechanism and the rate at which air can exhaust. The number of valves leads both to complexity and expense of the valve block.
Valve blocks have been proposed in which cylindrical cavities are provided in the valve block with passages leading to a supply of compressed air and to a consumer of such air opening into an end face of the cavity, with the valve to control the supply of air to the consumer being positioned in such cavity.